Eco-friendly polyester fibers and microfiber shed-resistance polyester textiles

ABSTRACT

The present application is generally concerned with polyester-based fibers, which exhibit enhanced resistance to breakage and attritional wear. More particularly, the inventive fibers may be especially aimed at textile applications, wherein the inventive fibers may reduce the propensity of the textile materials to produce microplastic and nanoplastic particles during use and during laundering or other cleaning operations, which are a known pollution hazard in the natural environment.

RELATED APPLICATIONS

This application claims the priority benefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application Ser. No. 62/885,536 entitled “ECO-FRIENDLY POLYESTER FIBERS AND MICROFIBER SHED-RESISTANCE POLYESTER TEXTILES,” filed Aug. 12, 2019, the entire disclosure of which is incorporated herein by reference.

BACKGROUND 1. Field of the Invention

The present invention is generally concerned with polyester-based fibers, which exhibit enhanced resistance to breakage and attritional wear. More particularly, the inventive fibers may be especially aimed at textile applications, wherein the inventive fibers may reduce the propensity of the textile materials to produce microplastic and nanoplastic particles during formation, use and during laundering or other cleaning operations, which are a known pollution hazard in the natural environment.

2. Description of the Related Art

The presence of visible plastics waste in the natural environment has been noted for many years, indeed almost since such materials first entered widespread use. While initially a nuisance, such pollution, especially in the marine environment, has grown to be a major concern. Large accumulations of pristine or damaged plastics-based products (“macroplastics”), such as packaging, fishing gear, and apparel, have been observed both in the open ocean and on beaches, often in remote locations far from likely sources of such materials.

More recently, there has been increasing concern regarding the presence of smaller size plastics pollution, commonly referred to as microplastics (i.e., plastics having a particle size of about 100 nm to about 5 mm) and nanoplastics (i.e., plastics having a particle size of about 100 nm or less), both of which may be generally classified as “microplastics.” Despite being largely invisible to the naked eye, many experts have expressed concern that such microplastics pollution could have a range of deleterious effects on the planetary ecosystem and food chains.

Initially, it was deduced that microplastics pollution was derived from two main sources: (1) primary microplastics and (2) secondary microplastics. Generally, primary microplastics refer to low particle size polymer particles deliberately produced for specific purposes. Potential sources of pollution of this type may include, for example, industrial waste from factories producing low particle size forms of polymers (e.g., in the form of emulsions or suspensions); particles used in cosmetic applications, such as skin exfoliants and dental products; abrasives preparations used in high-pressure cleaning formulations for the likes of buildings, roadways, and ships; and, more recently, very low particle size polymers used in 3D printing inks and in drug delivery systems. Alternatively, secondary microplastics generally refer to small particles produced by the physical and/or chemical degradation of macroplastics already present in the environment.

Within the last decade or so, compelling evidence has been found that a major source of microplastics pollution, especially in the marine, riparian, and littoral environments, is polymeric microfibers. Such microfibers appear to be mainly derived from commercial and domestic laundering, or other cleaning processes, carried out on textiles, in the form of apparel, bedding, soft furnishings, carpets, etc. Thus, a third source of microplastics pollution may include microfibers, which generally refers to small polymer particles derived predominantly from commercial or domestic laundering or cleaning of textiles and other fibrous products. Such pollution can be carried into the marine environment via untreated wastewater; from waste-water treatment plants, whose filters may be inadequate for trapping such small particles; and via rainwater run-off carrying microfibers deposited, by filtrate compost or whatever means, from the land environment. The microplastics from these sources may be derived from the textiles in any of a number of ways including, for example, loose fibers within the textiles as-made; broken sections of fiber, especially from fiber ends; and abraded particles from fiber surfaces. All such microplastics may be produced by wear of the textiles in use, and by damage inflicted within the textile or on the textile during the laundering/cleaning process itself.

Various studies have been, and are being, carried out to ascertain the extent of the microplastics problem. Of especial interest is information on the proportions of the various types of the microplastics. From currently available data, it is estimated that at least a third of all microplastics pollution is in the form of microfibers. Of these microfibers, it has been shown that polyester-based fibers constitute at least half of the man-made fiber-derived pollution.

The problem of primary microplastics pollution may be largely tackled by legislation, i.e., by implementing stricter rules for plastics producers, and restricting the use of polymer microparticles in certain consumer products. Indeed, many countries have already banned the use of polymer microbeads in cosmetic preparations.

In the same way, secondary microplastics may be reduced by the use of legal sanctions on dumping of macroplastics, and/or greater incentives for plastics recycling. This does not, however, solve the problem of microplastics from macroplastics already present in the environment.

In alternative treatments, some methods for filtering out microplastics from littoral environments have been suggested, such as in U.S. Pat. No. 8,944,253.

In the case of microfibers, legislation is a less useful weapon, and other approaches of a more technical nature are required.

Attempts have been made to provide washing machines with filters to capture microfibers, such as shown in WO 2019/045632. However, such filters may rapidly clog up, requiring frequent cleaning or replacement, and there still exists the need to safely dispose of the collected microfibers.

Another possible approach is to provide a simple device which can be placed in the washing machine alongside the laundry to prevent microfibers being expelled into the wastewater system. One such device is a plastic ball-shaped item capable of capturing and holding microfibers as shown in U.S. D833698 and U.S. Patent Application Publication No. 2019/0126326, while U.S. Patent Application Publication No. 2018/0320306 discloses a bag into which one or more laundry items may be placed, which consists of a material capable of filtering out microfibers. While such devices may be effective to some extent, the collected microfibers need to be removed from these devices and, again, require safe disposal.

Rather than attempting to collect microfibers before they can pass into the environment, it would be better to produce fibers which have a lower propensity for producing microfibers in the first place. However, attempting to replace current standard fiber-forming and textile-applicable fibers with an entirely new polymer with such properties is not an economically viable option. Thus, what is required is a means of producing fibers based on currently used polymers that shed a minimal amount of microfibers during use and laundering/cleaning whilst being fully suitable for current coloration, finishing, and fabrication technologies.

A method of achieving this goal has been suggested by De Falco et al., Carbohydrate Polymers, 198, 175, (2018), in which polyamide fibers are surface grafted with a reactive species containing a pectin group. While their results suggest that this process is effective in reducing microfiber production from such fibers, the approach appears to be restricted to polyamides, and involves a number of chemical and physical processes in addition to the basic melt-spinning of the fiber.

Accordingly, there is still a need for the production of fibers that may help mitigate microplastics pollution.

SUMMARY

One or more embodiments of the present invention are generally concerned with a melt-spun polyester fiber for reducing microplastics pollution. Generally, the melt-spun polyester fiber is in the form of: (i) a first core-sheath bicomponent polyester fiber comprising a first core domain and a first sheath domain, wherein the first core domain comprises a fiber-forming poly(alkylene terephthalate) and the first sheath domain comprises a homopolyester or copolyester that is different from the fiber-forming poly(alkylene terephthalate); (ii) a second core-sheath bicomponent polyester fiber comprising a second core domain and a second sheath domain, wherein the second core domain comprises a fiber-forming poly(alkylene terephthalate) and the second sheath domain comprises a homopolyester or copolyester and at least one shed-resistance additive; or (iii) a monocomponent polyester fiber comprising a fiber-forming poly(alkylene terephthalate), wherein the monocomponent polyester fiber is at least partially coated with a shed-resistance coating.

One or more embodiments of the present invention are generally concerned with a melt-spun polyester fiber for reducing microplastics pollution. Generally, the melt-spun polyester fiber is in the form of: (i) a core-sheath bicomponent polyester fiber comprising a core domain and a sheath domain, wherein the core domain comprises a poly(alkylene terephthalate) and said sheath domain comprises a homopolyester or copolyester and at least one shed-resistance additive; or (ii) a monocomponent polyester fiber comprising a poly(alkylene terephthalate), wherein the monocomponent polyester fiber is at least partially coated with a shed-resistance coating.

One or more embodiments of the present invention are generally concerned with a melt-spun polyester fiber for reducing microplastics pollution. Generally, the melt-spun polyester fiber is in the form of: (i) a first core-sheath bicomponent polyester fiber comprising a first core domain and a first sheath domain, wherein the first core domain comprises a fiber-forming poly(alkylene terephthalate) and the first sheath domain comprises a homopolyester or copolyester that is different from the fiber-forming poly(alkylene terephthalate); (ii) a second core-sheath bicomponent polyester fiber comprising a second core domain and a second sheath domain, wherein the second core domain comprises a fiber-forming poly(alkylene terephthalate) and the second sheath domain comprises a homopolyester or copolyester and at least one shed-resistance additive; or (iii) a monocomponent polyester fiber comprising a fiber-forming poly(alkylene terephthalate), wherein the monocomponent polyester fiber is at least partially coated with a shed-resistance coating. Furthermore, the melt-spun polyester fiber exhibits a fiber weight loss after a washing cycle of less than 2 weight percent and a waste microfibers loss per gram of tested sample after a washing cycle of less than 10 mg of waste microfibers.

One or more embodiments of the present invention are generally concerned with a method for producing the melt-spun polyester fibers described herein. Generally, the methods involve melt spinning a poly(alkylene terephthalate) to thereby form the melt-spun polyester fiber.

DETAILED DESCRIPTION

In order to provide an approach that reduces microfiber production from fibers and textiles by the greatest possible amount, and in an economically viable manner, a melt-extrusion process has been devised for the production of polyester fibers, which may provide fibers and textiles that have a significantly reduced propensity for producing microfibers during use and laundering/cleaning.

More particularly, the present invention is generally concerned with producing polyester fibers exhibiting a reduced propensity for breakage and attritional wear, which may be primarily produced using standard fiber-forming polyester. This may be achieved through the use of melt-spinning techniques and/or downstream physicochemical treatments.

As discussed below in greater detail, the inventive fibers described herein may take the form of a variety of embodiments. It should be noted that all of the following properties and ranges concerning the inventive fibers are not mutually exclusive (unless otherwise noted) and, therefore, may be combined in any manner by one skilled in the art as so desired. For example, any one of the thickness ranges could be combined with any one of the weight percentage ranges.

In one or more embodiments, the inventive fibers can be in the form of core-sheath fibers comprising different polyesters as the sheath domain and core domain. Additionally or alternatively, in various embodiments, the inventive fibers may be in the form of a core-sheath bicomponent melt-spun fiber, wherein the sheath comprises the same or a different polyester as the core and the sheath contains certain additives and/or a coating that aid reduction in microfiber loss from the inventive fiber.

Additionally or alternatively, in various embodiments, a coating/spin-finish may be applied on a melt-spun polyester monocomponent fiber or the sheath domain of a core-sheath bicomponent melt-spun fiber, wherein the coating/spin-finish places special additives onto the monocomponent fiber or the sheath domain, which may aid in the reduction in microfiber loss.

As noted above, in certain embodiments, one method of mitigating microfiber pollution involves melt-spinning a core-sheath bicomponent fiber having a standard fiber-forming polyester as a core domain and a sheath domain of an alternative polyester. The polyester of the sheath domain may be selected from polyesters that: (i) adhere well to the standard fiber-forming polyester of the core domain, (ii) have physical properties that reduce breakage of the core-sheath bicomponent fiber, and/or (iii) are less susceptible to attritional damage compared to the standard fiber-forming polyester of the core domain.

As noted above, in certain embodiments, another method of mitigating microfiber pollution involves melt-spinning a core-sheath bicomponent fiber having a standard fiber-forming polyester core domain and a sheath domain of the same polyester or a different polyester. In such embodiments, the sheath domain may contain one or more additives and/or a coating that act in such a manner as to provide fibers with a reduced propensity for breakage and/or attritional damage when exposed to laundering processes, especially when compared to fibers made entirely from the polyester of the core domain.

As noted above, in certain embodiments, yet another method of mitigating microfiber pollution involves melt-spinning a standard fiber-forming polyester into a monocomponent fiber and downstream treating the fiber with a lubricant or other coating formulation, wherein the lubricant or coating formulation contains one or more additives that, when coated onto or impregnated into the polyester fiber, act in such a manner as to provide polyester fibers with reduced propensity for breakage and/or attritional damage when exposed to laundering processes.

All of the above-referenced embodiments are described in greater detail below. It should be noted that, while some of the following characteristics and properties of the fibers may be listed separately, it is envisioned that each of the following characteristics and/or properties of the fibers are not mutually exclusive and may be combined and present in any combination as long as they do not conflict.

In various embodiments, the shed-resistant fibers of the present invention can comprise core-sheath bicomponent fibers that exhibit a reduced propensity for breakage and/or attritional wear, thereby significantly reducing the amount of microfiber pollution generated from the fibers and textiles made therefrom. In such embodiments, the core-sheath fibers can be produced from any melt spinning process known in the art. Generally, a core-sheath fiber is formed by a core domain being partially or, in most cases, fully encompassed by the sheath domain.

In certain embodiments, the core-sheath fibers may comprise a core domain at least partially formed by a fiber-forming polyester and a sheath domain at least partially formed by a different polyester. In alternative embodiments, the core-sheath fibers may comprise a core domain at least partially formed by a fiber-forming polyester and a sheath domain at least partially formed by the same polyester.

The core-sheath bicomponent fibers may be of any suitable overall cross-sectional shape, including, but not limited to, round, square, triangular, flattened, regular multilobal, and irregular multilobal.

The core domain of the core-sheath bicomponent fibers may be of any suitable cross-sectional shape, the shape being the same as or different from the overall cross-sectional shape of the core-sheath fibers, including, but not limited to, round, square, triangular, flattened, regular multilobal, and irregular multilobal.

The sheath domain of the core-sheath bicomponent fibers may cover the entire perimeter of the core domain of the fibers. Additionally, in various embodiments, the thickness of the sheath domain may constitute 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, or 5% or less of the average radius of the core-sheath fibers. Additionally or alternatively, in various embodiments, the core-sheath bicomponent fibers may comprise at least 1, 2, 5, 10, or 15 percent by volume and/or less than 50, 45, 40, 35, 30, 25, 20, 15, or 10 percent by volume of the sheath domain based on the total volume of the bicomponent fibers. Furthermore, in various embodiments, the core-sheath bicomponent fibers may comprise at least 10, 15, 20, 25, 30, 35, 40, 45, or 50 percent by volume and/or less than 95, 90, 85, 80, 75, 70, 65, 60, or 55 percent by volume of the core domain based on the total volume of the bicomponent fibers.

Furthermore, in various embodiments, the interface between the core domain and the sheath domain of the core-sheath bicomponent fibers may be smooth, may comprise of regular multiple peaks and troughs, or may comprise of irregular multiple peaks and troughs.

In one or more embodiments, the core domain of the core-sheath bicomponent fiber may be at least partially formed or entirely formed from a fiber-forming poly(alkylene terephthalate) polyester. In such embodiments, the alkylene moiety may be derived from a C₂₋₁₀ aliphatic diol or a derivative thereof, and is preferably selected from 1,2-ethanediol, 1,3-propanediol, and 1,4-butanediol. In certain embodiments, the core domain of the core-sheath bicomponent fiber may be at least partially formed or entirely formed from poly(1,2-ethylene terephthalate), poly(1,3-propylene terephthalate), poly(1,4-butylene terephthalate), or combinations thereof. In particular embodiments, the core domain of the core-sheath bicomponent fiber may be at least partially formed or entirely formed from poly(1,2-ethylene terephthalate). In even more particular embodiments, the core domain of the core-sheath bicomponent fiber may be at least partially formed or entirely formed from a non-biodegradable polyester.

In one or more embodiments, the core domain of the core-sheath bicomponent fiber may comprise at least 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 99 weight percent of at least one poly(alkylene terephthalate) polyester.

Additionally or alternatively, in one or more embodiments, the sheath domain of the core-sheath bicomponent fiber may be at least partially formed or entirely formed from a fiber-forming poly(alkylene terephthalate) polyester. In such embodiments, the alkylene moiety may be derived from a C₂₋₁₀ aliphatic diol or a derivative thereof, and is preferably selected from 1,2-ethanediol, 1,3-propanediol, and 1,4-butanediol. In certain embodiments, the sheath domain of the core-sheath bicomponent fiber may be at least partially formed or entirely formed from poly(1,2-ethylene terephthalate), poly(1,3-propylene terephthalate), poly(1,4-butylene terephthalate), or combinations thereof. In particular embodiments, the core domain of the core-sheath bicomponent fiber may be at least partially formed or entirely formed from poly(1,4-butylene terephthalate). In particular embodiments, the sheath domain of the core-sheath bicomponent fiber may be at least partially formed or entirely formed from a non-biodegradable polyester.

Additionally or alternatively, in one or more embodiments, the sheath domain of the core-sheath bicomponent fiber may comprise at least 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 99 weight percent of at least one poly(alkylene terephthalate) polyester.

In one or more embodiments, the sheath domain of the core-sheath bicomponent fibers may comprise a homopolyester, wherein the homopolyester is different from or the same as the polyester forming the core domain of the fiber. In such embodiments, the homopolyester may comprise a poly(alkylene carboxylate), a poly(cycloalkylene carboxylate), a poly(arylene carboxylate), a poly(aralkylene carboxylate), or combinations thereof. The carboxylate moiety in any of the homopolyesters may be derived from an aromatic dicarboxylic acid, an araliphatic dicarboxylic acid, an aliphatic dicarboxylic acid, a cycloaliphatic dicarboxylic acid, a hetroaromatic dicarboxylic acid, a heteroaliphatic dicarboxylic acid, a heterocycloaliphatic dicarboxylic acid, or derivatives thereof.

In one or more embodiments, the sheath domain of the core-sheath bicomponent fibers may comprise a copolyester, wherein the copolyester contains moieties derived from diols or derivatives thereof and moieties derived from dicarboxylic acids or derivatives thereof.

The diols used to produce the polyesters may comprise, for example, straight chain aliphatic diols, branched aliphatic diols, unsubstituted cycloaliphatic diols, substituted cycloaliphatic diols, unsubstituted aromatic diols, substituted aromatic diols, unsubstituted araliphatic diols, substituted araliphatic diols, straight chain heteroaliphatic diols, branched heteroaliphatic diols, unsubstituted heterocycloaliphatic diols, substituted heterocycloaliphatic diols, unsubstituted heteroaromatic diols, substituted heteroaromatic diols, unsubstituted heteroaraliphatic diols, substituted heteroaraliphatic diols, or combinations thereof.

The dicarboxylic acids used to produce the polyesters may comprise, for example, straight chain aliphatic dicarboxylic acids, branched aliphatic dicarboxylic acids, unsubstituted cycloaliphatic dicarboxylic acids, substituted dicarboxylic acids, unsubstituted aromatic dicarboxylic acids, substituted dicarboxylic acids, unsubstituted araliphatic dicarboxylic acids, substituted araliphatic dicarboxylic acids, straight chain heteroaliphatic dicarboxylic acids, branched heteroaliphatic dicarboxylic acids, unsubstituted heterocycloaliphatic dicarboxylic acids, substituted heterocycloaliphatic dicarboxylic acids, unsubstituted heteroaromatic dicarboxylic acids, substituted heteroaromatic dicarboxylic acids, unsusbstituted heteroaraliphatic dicarboxylic acids, substituted heteoaraliphatic dicarboxylic acids, or combinations thereof.

In one or more embodiments, the sheath domain may comprise at least two layers, including an inner layer and an outer layer. The inner layer may be at least partially formed or entirely formed from a homopolyester or copolyester that exhibits a compatibilization or adhesion function, while the outer layer may be at least partially formed or entirely formed from a homopolyester or copolyester that provides the desired resistance to breakage and/or attritional damage. In such embodiments, the homopolyester or copolyester of the inner layer may be different from that of the outer layer. Furthermore, the inner layer and the outer layer may be formed from the homopolyesters and copolyesters hereinbefore described. In certain embodiments, the inner layer may completely encompass and cover the core domain and the outer layer may at least partially encompass or entirely encompass the inner layer.

In one or more embodiments, the polyesters and/or the diols and diacids used in the preparation of the polyesters may be derived from one or more of petrochemical resources, renewable resources, and/or recycled resources.

Alternatively, in various embodiments, the shed-resistant fibers of the present invention can comprise monocomponent fibers that exhibit a reduced propensity for breakage and/or attritional wear, thereby significantly reducing the amount of microfiber pollution generated from the fibers and textiles made therefrom. In such embodiments, the monocomponent fibers can be produced from any melt spinning process known in the art. It should be noted that the monocomponent fibers may be produced by the homopolyesters and copolyesters hereinbefore described.

In one or more embodiments, the sheath domain of the core-sheath fibers or the monocomponent fibers may comprise one or more shed-resistance additives, which may alter the physical properties of the sheath domain polyester or of the polyester forming the monocomponent fiber in such a way so as to form fibers with a reduced propensity towards breakage and/or attritional damage. Consequently, this can result in the production of fibers, yarns, and textiles that may shed significantly lower amounts of microfibers during use and laundering. In the case of the core-sheath fibers containing a sheath domain with multiple layers, the shed-resistance additives may be present in all the layers or separate distinct layers (e.g., the additives may be present in the outer layer, but absent in the inner layer). Exemplary shed-resistance additives can include, for example, lubricants, impact modifiers, crosslinkers and chain extenders, crystallization modifiers, low molecular weight substances such as oligomers or polymers, or combinations thereof. In certain embodiments, the fibers of the present invention may comprise at least 0.1, 0.5, 1, 2, 3, 4, or 5 and/or not more than 50, 45, 40, 35, 30, 25, 20, 15, 10, 5, or 1 weight percent of at least one shed-resistance additive.

Lubricants may include, but are not limited to, one or more of hydrocarbons, fluorocarbons, or silicones, such as organosilicon polymers.

Impact modifiers may include, but are not limited to, one or more of rubbers, addition copolymers, condensation copolymers, microspheres, or fibers.

Crosslinkers and chain extenders may include, but are not limited to, one or more of polyols, polyamines, polyacids, or silanes.

Crystallization modifiers may include, but are not limited to, one or more crystallization nucleating agents and/or one or more crystallization suppression agents.

In one or more embodiments, the sheath domain of the core-sheath fibers or the monocomponent fibers may comprise a shed-resistance coating or lubricant. In such embodiments, the core-sheath fibers or the monocomponent fibers may be surfaced treated or subjected to a lubricant in a continuous or discontinuous manner after melt spinning. The coating formulation or lubricant may contain one or more additives which, when coated onto, or impregnated into, the outer region of the fibers, provides the fibers with a reduced propensity towards breakage and/or attritional damage. Consequently, this can result in the production of fibers, yarns, and textiles that may shed significantly lower amounts of microfibers during use and laundering. In certain embodiments, the fibers of the present invention may comprise at least 0.1, 0.5, 1, 2, 3, 4, or 5 and/or not more than 50, 45, 40, 35, 30, 25, 20, 15, 10, 5, or 1 weight percent of at least one shed-resistance coating or lubricant. It should be noted that the shed-resistance coating or shed-resistance lubricant may comprise one or more of the above-referenced shed-resistance additives.

In one or more embodiments, the polyesters forming the core domain, the sheath domain, and/or the monocomponent fibers may optionally comprise active formulation additives. Such active formulation additives may include, but are not limited to, colorants, UV stabilizers, antioxidants, metal deactivators, nucleating agents, fire retardants, particulate or fibrous fillers, antimicrobials, antistatics, processing aids, and combinations thereof. In certain embodiments, the fibers of the present invention may comprise at least 0.1, 0.5, 1, 2, 3, 4, or 5 and/or not more than 50, 45, 40, 35, 30, 25, 20, 15, 10, 5, or 1 weight percent of at least one active formulation additive.

In one or more embodiments, the polyesters forming the core domain, the sheath domain, and/or the monocomponent fibers may not contain any plasticizers, carbon black, and/or antimicrobial additives, such as zeolites or metal-based antimicrobial agents (e.g., metal-based antimicrobial agents, such as silver-based agents). For instance, the core domain and/or the sheath domain of the core-sheath fibers or the monocomponent fibers may comprise less than 1, 0.5, 0.1, 0.05, 0.01, 0.005, or 0.001 weight percent of plasticizers, carbon black, and/or antimicrobial additives.

In one or more embodiments, the bicomponent fibers and/or the monocomponent fibers may comprise a deniers per filament (“dpf”) of at least 0.1, 0.5, 1, 2, or 3 and/or not more than 20, 15, 10, 9, 8, 7, 6, 5, or 4 dpf.

As noted above, the core-sheath fibers and the monocomponent fibers of the present invention may be melt-spun using equipment and methods known to those skilled in the art. Exemplary melt spinning equipment and techniques are described in U.S. Pat. Nos. 5,162,074 and 6,783,854, the disclosures of which are incorporated herein by reference in their entireties.

The core-sheath fibers and the monocomponent fibers of the present invention may be produced in any suitable form, including, but limited to, multifilament yarns, staple fiber and yarns, monofilaments, thermoplastic composites, and non-wovens. The fibers or yarns melt-spun in this manner may be subjected to known downstream processing methods, including, but not limited to, hot or cold drawing, texturing, heat-setting, cutting, fusing, and/or batt formation.

Due to the unique shed-resistance properties, the fibers of the present invention may exhibit a fiber weight loss after a washing cycle of less than 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.05, or 0.01 weight percent. The washing cycle for this test can be carried out at 40° C. for 30 minutes at 1,400 rpm and in the absence of a detergent. The fibers or sample textile can be dried after the washing cycle at 80° C. for 24 hours. The mass of the resulting fiber mass or sample textile can then be measured and compared against the initial mass of the fibers or sampled textile to calculate the percent fiber loss.

Additionally, due to the unique shed-resistance properties, the fibers of the present invention may exhibit a waste microfibers loss per gram of tested sample after the above-referenced washing cycle of less than 100, 75, 50, 40, 30, 20, 15, 10, 5, 1, 0.5, 0.1, 0.05, or 0.01 mg of waste microfibers. As used herein, “waste microfibers” refer to fibers derived from the tested sample during the washing cycle and that have an average length of less than 5 mm and an average diameter of less than 50 microns.

Furthermore, due to the unique shed-resistance properties, the fibers of the present invention may exhibit a percent reduction in microparticle area of at least 10, 15, 20, 25, 30, 35, 40, or 45 percent and/or not more than 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, or 30 percent, as calculated with ImageJ software after laundering in accordance with test method AATCC TM 61 and based on laundering regime 2A or 3A. In regime 2A, the wash canister contains 150 ml of wash water and 50 steel balls, and the temperature is set at 49±2° C. In regime 3A, the wash canister contains 50 ml of wash water and 100 steel balls, with the temperature set at 71±2° C. In both regimes, the wash water also contains 0.15% detergent and the wash-cycle time is 45 minutes.

The fibers or yarns of the present invention may be used in the manufacture of various woven, knitted, tufted, webbed, and/or non-woven textiles or in the manufacture of woven, knitted, non-woven, and/or tufted floorcoverings. The textiles produced from the fibers or yarns of the present invention may also be used in the manufacture of finished goods, including, but not limited to, apparel, towels, soft furnishings, and bedding.

Moreover, as the core-sheath bicomponent fibers and the monocomponent fibers of the present invention are made entirely of polyesters derived from dicarboxylic acids and diols, the fibers or articles made therefrom can, at the end of their useful life, be chemically recycled to starting materials using methods known to those skilled in the art.

This invention can be further illustrated by the following examples of embodiments thereof, although it will be understood that these examples are included merely for the purposes of illustration and are not intended to limit the scope of the invention unless otherwise specifically indicated.

EXAMPLES Examples 1-5 and Comparative Example 6

Multifilament yarns of 100 denier and comprising 36 filaments per yarn and a final draw ratio of about 2.8 were melt spun using equipment and processes familiar to those skilled in the art. The inventive yarns of Examples 1-5 comprised filaments of a core-sheath bicomponent configuration, wherein the core domain constituted 85 percent by volume of the overall filament and the sheath domain constituted 15 percent by volume of the overall filament. Furthermore, the core domains of Examples 1-5 were formed from poly(ethylene terephthalate) (“PET”) and the sheath domain were formed from a thermoplastic polyester optionally containing a shed-resistant additive package comprising polymeric and/or non-polymeric constituents. The formulations of the sheath domains in Examples 1-5 are provided below in TABLE 1.

TABLE 1 Example Sheath Formulation 1 PET containing an additive package of organosilicon polymers for softening and/or smoothing of the matrix polyester 2 PET containing an additive package of active adjuvants for thermal and thermo- oxidative stabilization of the matrix polyester 3 PET containing an additive package consisting of active adjuvants for hydrolytic stabilization and intrinsic viscosity enhancement of matrix polyester 4 PET containing an additive package of active adjuvants for crystallization control of the matrix polyester 5 Poly(butylene terephthalate)

For Comparative Example 6, a yarn consisting of poly(ethylene terephthalate) monofilaments of the same overall denier and fiber count was melt-spun under the same conditions as used for the manufacture of Examples 1-5.

The inventive yarns noted in TABLE 1, along with the comparative poly(ethylene terephthalate) yarn, were each single thread-line jersey knitted into socks. Two distinctive analytical methods were used to describe the rate of microfiber shed: (i) analysis of deposited microfiber shed on filtration media and (ii) particle analysis of shed microfibers using ImageJ.

For testing the accelerated wear and collected microfiber shed, samples measuring 3.5 inches by 5 inches were cut from the socks, and the edges thereof heat-sealed and trimmed to remove rough edges.

The aforementioned samples were then subjected to simulated wear using a model CM1 Crockmeter (Atlas Electric Devices). Fabric samples were attached to the stationary bottom portion of the Crockmeter, while a stainless-steel screen with 25 mm pore size was attached to the oscillating upper portion. The stainless-steel screen was oscillated against each fabric surface 30 times to generate wear on the samples.

Visual examination of the tested samples noted that all inventive samples exhibited less wear than the comparative sample when passed through a multi-stage filter of 200×200 μm, 100×100 μm, 25×25 μm, and 450 nm, in series. A quantitative measurement, using the same abrasion and laundering procedure of the replicate samples described above with the Crockmeter, was collected using a single 10×10 micrometer filter. More particularly, after the laundering procedure with the Crockmeter, the samples were placed in 1 liter Laundr-O-meter canisters and tested using optimized conditions to generate wear on the samples (2 hours, 45° C., 50 stainless steel balls, 200 g DI water). The fabric was then allowed to dry. The resulting laundry water was also filtered using an approximate 10 μm filter to compare lint generation between samples (sample mass). The collected material was weighed, and the results are given in TABLE 2, below.

TABLE 2 Percent Reduction in Microparticle Example Mass Generated in Laundering 1 20 2 39 3 41 4 35 5 41

For particle analysis in laundering water, testing of samples was carried out using a standard test apparatus, in the form of an SDL Atlas Laundr-O-Meter M228 Rotowash. The test protocols used were those described in the test method AATCC TM 61 “Test method for colorfastness in laundering,” which is incorporated herein by reference in its entirety.

Two laundering regimes were used in the tests in an attempt to simulate both standard and harsher washing cycles likely to be encountered during domestic or commercial laundering. The two regimes were referred to as “2A” and “3A.” In regime 2A, the wash canister contained 150 ml of wash water and 50 steel balls, and the temperature was set at 49±2° C. In regime 3A, the wash canister contained 50 ml of wash water and 100 steel balls, with the temperature set at 71±2° C. In both regimes, the wash water also contained 0.15% detergent and the wash-cycle time was 45 minutes.

Samples of the test fabrics and samples of the control fabrics were subjected to both laundering regimes in the device canisters, along with a canister containing no sample as a blank. Following laundering, water samples were extracted from the wash canisters and prepared for imaging using microscopy.

Results of the laundering tests are provided below in TABLE 3 as a percentage reduction in microparticle area as calculated in ImageJ using the particle analysis tools of the ImageJ software, with respect to the control poly(ethylene terephthalate) fabric.

TABLE 3 Example Regime 2A Regime 3A 1 31 10 2 35 28 3 41 47 4 3 34 5 42 —

Definitions

It should be understood that the following is not intended to be an exclusive list of defined terms. Other definitions may be provided in the foregoing description, such as, for example, when accompanying the use of a defined term in context.

As used herein, the terms “a,” “an,” and “the” mean one or more.

As used herein, the term “and/or,” when used in a list of two or more items, means that any one of the listed items can be employed by itself or any combination of two or more of the listed items can be employed. For example, if a composition is described as containing components A, B, and/or C, the composition can contain A alone; B alone; C alone; A and B in combination; A and C in combination, B and C in combination; or A, B, and C in combination.

As used herein, the terms “comprising,” “comprises,” and “comprise” are open-ended transition terms used to transition from a subject recited before the term to one or more elements recited after the term, where the element or elements listed after the transition term are not necessarily the only elements that make up the subject.

As used herein, the terms “having,” “has,” and “have” have the same open-ended meaning as “comprising,” “comprises,” and “comprise” provided above.

As used herein, the terms “including,” “include,” and “included” have the same open-ended meaning as “comprising,” “comprises,” and “comprise” provided above.

Numerical Ranges

The present description uses numerical ranges to quantify certain parameters relating to the invention. It should be understood that when numerical ranges are provided, such ranges are to be construed as providing literal support for claim limitations that only recite the lower value of the range as well as claim limitations that only recite the upper value of the range. For example, a disclosed numerical range of 10 to 100 provides literal support for a claim reciting “greater than 10” (with no upper bounds) and a claim reciting “less than 100” (with no lower bounds).

CLAIMS NOT LIMITED TO DISCLOSED EMBODIMENTS

The preferred forms of the invention described above are to be used as illustration only and should not be used in a limiting sense to interpret the scope of the present invention. Modifications to the exemplary embodiments, set forth above, could be readily made by those skilled in the art without departing from the spirit of the present invention.

The inventors hereby state their intent to rely on the Doctrine of Equivalents to determine and assess the reasonably fair scope of the present invention as it pertains to any apparatus not materially departing from but outside the literal scope of the invention as set forth in the following claims. 

What is claimed is:
 1. A melt-spun polyester fiber for reducing microplastics pollution, wherein said melt-spun polyester fiber is in the form of: (i) a core-sheath bicomponent polyester fiber comprising a core domain and a sheath domain, wherein said core domain comprises a poly(alkylene terephthalate) and said sheath domain comprises a homopolyester or copolyester and at least one shed-resistance additive; or (ii) a monocomponent polyester fiber comprising a poly(alkylene terephthalate), wherein said monocomponent polyester fiber is at least partially coated with a shed-resistance coating.
 2. The melt-spun polyester fiber according to claim 1, wherein said poly(alkylene terephthalate) comprises poly(1,2-ethylene terephthalate), poly(1,3-propylene terephthalate), or poly(1,4-butylene terephthalate), and wherein said homopolyester or said copolyester comprises poly(1,2-ethylene terephthalate), poly(1,3-propylene terephthalate), or poly(1,4-butylene terephthalate).
 3. The melt-spun polyester fiber according to claim 2, wherein said melt-spun polyester fiber is said core-sheath bicomponent polyester fiber.
 4. The melt-spun polyester fiber according to claim 3, wherein said sheath domain comprises an inner layer and an outer layer.
 5. The melt-spun polyester fiber according to claim 4, wherein said inner layer and said outer layer are formed from different polyesters.
 6. The melt-spun polyester fiber according to claim 3, wherein said melt-spun polyester fiber comprises 0.1 to 25 weight percent of said shed-resistance additives.
 7. The melt-spun polyester fiber according to claim 6, wherein said shed-resistance additives comprise a lubricant, an impact modifier, a crosslinker, a chain extender, a crystallization modifier, or combinations thereof.
 8. The melt-spun polyester fiber according to claim 1, wherein said melt-spun polyester fiber is said monocomponent polyester fiber.
 9. The melt-spun polyester fiber according to claim 8, wherein said melt-spun polyester fiber comprises 0.1 to 25 weight percent of said shed-resistance coating, wherein said shed-resistance coating comprises one or more shed-resistance additives.
 10. The melt-spun polyester fiber according to claim 9, wherein said shed-resistance additives comprise a lubricant, an impact modifier, a crosslinker, a chain extender, a crystallization modifier, or combinations thereof.
 11. The melt-spun polyester fiber according to claim 1, wherein said melt-spun polyester fiber exhibits a fiber weight loss after a washing cycle of less than 2 weight percent.
 12. The melt-spun polyester fiber according to claim 1, wherein said melt-spun polyester fiber exhibits a waste microfibers loss per gram of tested sample after a washing cycle of less than 10 mg of waste microfibers.
 13. A textile comprising said melt-spun polyester fiber according to claim
 1. 14. An article of manufacture comprising said melt-spun polyester fiber according to claim
 1. 15. A method for forming said melt-spun polyester fiber according to claim 1, said method comprising melt spinning said poly(alkylene terephthalate) to thereby form said melt-spun polyester fiber.
 16. A melt-spun polyester fiber for reducing microplastics pollution, wherein said melt-spun polyester fiber is in the form of: (i) a first core-sheath bicomponent polyester fiber comprising a first core domain and a first sheath domain, wherein said first core domain comprises a poly(alkylene terephthalate) and said first sheath domain comprises a homopolyester or a copolyester that is different from said fiber-forming poly(alkylene terephthalate); (ii) a second core-sheath bicomponent polyester fiber comprising a second core domain and a second sheath domain, wherein said second core domain comprises a poly(alkylene terephthalate) and said second sheath domain comprises a homopolyester or a copolyester and at least one shed-resistance additive; or (iii) a monocomponent polyester fiber comprising a poly(alkylene terephthalate), wherein said monocomponent polyester fiber is at least partially coated with a shed-resistance coating, wherein said melt-spun polyester fiber exhibits a fiber weight loss after a washing cycle of less than 2 weight percent, and wherein said melt-spun polyester fiber exhibits a waste microfibers loss per gram of tested sample after a washing cycle of less than 10 mg of waste microfibers.
 17. The melt-spun polyester fiber according to claim 16, wherein said poly(alkylene terephthalate) comprises poly(1,2-ethylene terephthalate), poly(1,3-propylene terephthalate), or poly(1,4-butylene terephthalate), and wherein said homopolyester or said copolyester comprises poly(1,2-ethylene terephthalate), poly(1,3-propylene terephthalate), or poly(1,4-butylene terephthalate).
 18. A textile comprising said melt-spun polyester fiber according to claim
 16. 19. An article of manufacture comprising said melt-spun polyester fiber according to claim
 16. 20. A method for forming said melt-spun polyester fiber according to claim 16, said method comprising melt spinning said poly(alkylene terephthalate) to thereby form said melt-spun polyester fiber. 